The area of use of the invention is especially in medical technology with the emphasis being in the area of ventilation and of monitoring of medical apparatus and the patients connected thereto who are being ventilated. To an increasing degree, monitoring parameters become also more important which do not themselves function for monitoring the patient or the apparatus status but afford a possibility to detect and to control the consumption of operating agents such as anesthetic gases. This is especially true, inter alia, because of the increasing cost pressures in medicine. A cost factor, which participates essentially with respect to an anesthesia, is the consumption of volatile anesthetic gases, namely, halothane, isoflurane, enflurane, sevoflurane and desflurane.
In most ventilation systems and especially in anesthesia apparatus, these volatile anesthetic agents are not electronically applied and especially vaporized but are rather applied via purely mechanical metering units which do not communicate electronically with the anesthesia apparatus. An example of an anesthetic agent metering device of this kind is available in the marketplace from Drager Medical AG & Co. KG under the product name “Vapor 2000”. Therefore, the consumptions of liquid volatile anesthetic agents, which are associated therewith, can not be directly determined and a consumption analysis cannot take place referred to a specific workplace or anesthetist. Especially in a low-flow anesthesia in a breathing circuit, the adjustment of the concentration at the anesthetic agent metering device (Vapor 2000) deviates greatly from the concentration measured at the patient so that no direct conclusion can be drawn from this measured value as to the anesthetic medium flow taken from the anesthetic agent metering device.
A measurement of the consumption of liquid volatile anesthetic agents does not take place with mechanical anesthetic agent vaporizers.